Manufacture of armor-piercing projectiles.



UNITED STATES PATENT curios.

ROBERT ABBOTT HADFIELD, OF WESTMINSTER, ALEXANDER G, M. JACK, OE SHEFFIELD, AND ISAAC BERNARD MILNE, OF TOTLEY, ENGLAND.

MANUFACTURE OF ARMOR-PI'ERCING PROJ'ECTILES.

No Drawing.v Application filed August 19, 1913,

To all whom it may concern Be it known that we, Ronnn'r Aeno'rr HADFIELD, knight, F. R. S., ALEXANDER GEORGE MCKENZIE .JAoK, and Isaac BER- NARD MILNE, respectively of 22 Carlton House Terrace, Westminster, Rockhills, Brinclitfe, Sheffield, Yorkshire, and Cross Grove House, Totley, in the county of Derby, subjects of the King of Great Britain and Ireland, have invented Improvements in or Relating to the Manufacture of Armor- Piercing Projectiles, of which the following is a specification. I

This invention has for its object to produce armor piercing projectiles, particularly of large diameters, say of twelve inches and upward, that shall be better adapted than heretofore to completely perforate-thick hard faced armor plates without becoming broken Al s up or broken to such an extent as to interferewith their subsequent desired action.

For this purpose an armor piercing shell according to the present invention is made of good steel, such as nickel chromium steel and subsequently treated in such a manner that the head or ogival forward portion of r the shell is of different degrees of hardness 300 extending rearward for a short distance around the shell cavity, the remainin rearward portion of the shell having a ball hardness under 300. In the production of such a'shell, made say of nickel chromium steel, the shell after being formed to shape, as by "casting it solid and then, after suitably annealing it, pressing it to shape in a suitable press, .is hardened by subjecting it to two separate treatments of which the first consists in heating the shell in a suitable furnace to a hardening temperature while protecting the point thereof from direct contact with the heating medium in a manner well understood, so that this shoulder po rtion of the projectile is raised to a higher temperature than the point and the point to a hi her temperature than the base, then dipping the shell point downward to its Specification of Letters Extent.

Patented May 11, 1915.

Seriiil No. 785.466. Renewed October 6, 1914. Serial No. 865,398.

base end in a cooling medium for example oil, then raising it for a certain distance and holding it raised for a time, then raising it still farther to a suitable zone depth for a certain time and then lowering it again to the base end. The second treatment consists in heating the base portion of the shell to a suitable tempering temperature while its pointed end portion is immersed to a suit able depth in water, after which it is immersed or quenched outright in a cooling medium for example water. The tempera-- tures to which the various parts of the shell. are heated. the depths and durations of i mersion and other details can be 1 l modified to suit different of the steel of which they are made. cases the shell may be subjected to a treatment after the character of the mentioned treatment.

According to one example, carried out with a twelve inch shell having a length of about thirty four inches and made of nickel chromium steel having the following approximate composition, namely carbon .6 to 17%; nickel to 3% and chromium 8, to 3%, for example carbon about 1736"" Ni about 2.52% and chromium abort, 2.31%, the shell was taper heated While its point was protected from direct contact with the heat, so that the external shordder portion of the shell had a temperature about 915 C. to 920 C. the inner surface or core adjacent to the shoulder portion a temperature of about 900 to 905 (3., the point a temperature of about 890 C. and the base a temperature of about 780" C. The shell thus heated was then dipped in oil to its base end and held there for about eight minutes, then raised in the oil about tweive inches and held in that position for about ten minucs. thcn raised to a zone depth say of about ten inches and held in that position for about twenty fire minutes, then lowered again to base end and water poured into its interior. The shell then subjected to a second treatment consisting .in heating the base in a furnace to a teminches. 311 at 18'inches and 241 at the base end of the shell. which had a length of about thirty four and a half inches.

According to another example carried out with a fourteen inch shell having a length of about fifty-two inches and made of nickel chromium steel having the following approximate composition viz carbon 09% nickel 1.53% and chromium 2.70%, the shell was tapi r heated while its point was protected direct contact with the heat so that tlle' external shoulder portion of the shell had a temperature of about. 930 (1, the inner surface or core adjacent to the shoulder a temperature of about 900 to 905 the point a temperature of about 875 C. and the base a temperature of shout 850 f. The shell thus heated was then dipped in oil to its )llSG end and held in that position for about 14 minutes. then raised in the oil about eighteen inches and held in that position for about four minutes then raised about six inches more and held for about six minutes and then raised to a zone depth of about-ele 'en inches and held there for eighteen minutes then lowered in the oil to its base end and about two gallons of water poured into its interior. The shell was then subjected to a second treatment consisting in heating the .base to a temperature of about 700 C. and its interior or core to a temperature of about 630 while I its point is immersed for about a depth of ight inches in water. The. shell was then allowed to cool down in the furnace t a base temperature of about 310 C. and a core teu'iperature of about 2 5 and then quenched outright in water. in this case the first eightinches had a ball hardness of G52 and over this portion constituting about 6"; of the weight of the shell the hardness decreasina t the base where t is about 262.

From the foregoing examples it will be seen that the temperatures to which the variousparts of the shell can be heated and the manipulation of the shell can be variously modified without departing from the essential features of the invention.

The ab ve menti ned temperatures'may be varied within a rangeof about upwa d or downward.

What we claim is The process of treating an armor piercing projectile which consistszin heating the shell to a hardening temperature, to bring the shoulder to a higher temperature than the point and the point to a-higher temperature than the base, then dipping the shell point downward toits base in a cooling medium, maintaining it in that position for a few minutes, raising it about one third of its length more or less and there maintaining it for a few minutes, then raising to about two-thirds of its length more or less and there maintaining for a somewhat longer time, then lowering in the medilfln to the base end and pouring Water into its interior.

The process of treating an armor piercing projectile which consists in heating the shell to a hardening temperature, to bring the shoulder to a higher temperature than the point and the point to a higher temperature than the base, then dipping the shell point downward to its base in oil, maintaining it in that position for a few minutes, raising it step-by-step from the oil and maintaining it in each position for a few minutes. then lowering in the medium to its base end and pouring water into its interior. then heating, the base while maintaining the end portion in water, then allowing the shell to cool down and then quenching it outright.

3. The process of treating an armor piercing projectile which consists in heating the shell to a hardening temperature, to bring the shoulder to a higher temperature than the point and the point to a higher temperature than the base, then dipping the shell point downward to its base in a cooling medium, maintaining it in that position for a few minutes, raising it about one third of its length more or, less and there maintain.- ing it for a few minutes, then raising to about two-thirds of its length more or less and there maintaining for a somewhat longer time, then lowering in the medium to the base end and pouring water into its interior, then heating the base to a substan tially lower temperature than the first heating while maintaining the end portion in a. cooling medium, then allowing the shell to cool down and then quenching it outright, substantially as described. s'

4. The herein described'process of hardening an armor piercing projectile which consists in a double treatment substantially as follows, first heating the external shoulder of the shell to about 920 to 930, more or l ss. the inner surface adjacent the shoulder to about 00" more or less, the point to 4 temperature'of about 875 to 880, more or less. and the base toa temperature substantiallv lower. then dipping the shell in oil to its base and maintaining it in that posi tion about eight to fourteen minutes, m ore or le s, then rai in ;f tilt shell in tlw 011 about one-third 111 1w hngjth atal maintain in}: it in that ptrsition 1111- t'titlltl' llltllt than vig'ht 11111111105 1111111 111' 11'; than 111191151 1t 5 to a zone depth 111 almnt UMP-1111111 11 11 hngith, more 11 lcss. anti 111ainta1n1-nj4 it in that position fur a luntfvr t1111t-. than havering! tht shtll intn 1111 oil tn it ham and pnnring \Vztttl 111t 1 it 1nt0110r. then rvheatinti' thv slit-ll hash to ahtatt 650 to T2!) 11141111 (1r .1ntl its t'tH't' to ahnnt W) to 6 1' more (11' loss, while its point is innnvrsctl in watt-r to I'tttlltl' less than (1110 third the shell length. then permitting the ltfli tn 1:110! tn :1 te111pv1'at11re of from about i- 111 m almut 2171 1" 111011 or less. a11-;l thvn qurnrhingi nntright 111 Water.

'i'hv process (11 treatin 1 an arnmr pivrr int: prnjta-tile which consists in heating thv aht-li tn bring the shonhler tn :1 higher t 111 peratnrc than tlw puint. dipping the shell pulnt tltmnn'aril 111 a t'OUlillQ' inetlinni, rai int! it partially 110111 Haiti lllt'tiilllll. than 1111111111 again into thc nmlhnn.

t2. 'lhtpmuvss of treating: an arnmr picrrh1g1 pru iwtih \Yliit'll cnnsists in heating the l1tll tn :1 liar-10111115: ttlllpti'ilhllt. prot'vct 11111 the paint 111111 bringing thv shnttltltl' to a highvr ttanpt-tatttre than thv point than at i11111a rs111g! the ahvli. point (lawn. 111 a cool ing 111011111111. raising the shall hut leaving a 1 111111111 111 milil 1111 11111111. than luwering the. hvll 111111 111v nnalhnn.

T, linl1l't1tt' 111' trt-atintr an arminpiercing prnim-tilv llltil mmista in ht-ating! the h1-ll 111:1 hartlrni11j ttHIIHF'HlllI While pr0- ti-rtinn' 1111- paint t 1 111-111; the h1111hh r to a hitt'hi-r {Ulilllt'tllltt than tilt puint and the pnint {11:1 higlwr tttlihtl'il'tlli't than the 1121.50, than dipping thv shvll point downward in a whaling lilt'tlllllll. raising thtshell in the 111011111111 sit)? l1 stvp tn a pinraliti v 0f posh tam. :HHi lllilllllillllllifl thv shall a short time in nath 11l' a1 l pUSlLlUnS.

N. 'lhtprm-vss (1f trt'atinfI an arnim pierc- 111;! [H'nltt'lllt whit-h roilsists 111 applying a prom-tar to thc point an as to protect the paint 1 111111 ilirvt't ()Ulltlltt with the heat, tlnn 11PHI1I11I tho shtll 111 a fnrnat-e to bring tln- :Jnmhlvr 1a a hight-r ttanpt-ratlwe than tl1ttruittt hin 1111111111; he shall in a 01101- in; 1111 11111111. point t1(1\-'1l\\til(l. partially rinsing: tln- 11t-ll 1111111 the nwtliann then l 1\\ 0 in thu ahvii into thv 1118111111111.

iam- 1 at iminlon; England. this sixth (lay (11' V \llgllfl 1 13. 

